Blast furnace stove burner assembly

ABSTRACT

A GAS BURNER FOR USE ON A BLAST FURNACE STOVE IS DISCLOSED WHEREIN THERE ARE INNER AND OUTER CONCENTRIC PASSAGES FOR THE AIR AND GAS. THERE IS A GATE VALVE INTERPOSED BETWEEN THE END OF THE BURNER, AND THE INNER PASSAGE IS PROVIDED WITH A TERMINAL SECTION THAT TELESCOPICALLY ENGAGES A FIXED INNER DUCT SECTION IN SUCH MANNER THAT IT CAN BE RETRACTED WHEN THE GATE VALVE IS TO BE CLOSED AND EXTENDED TO OPERATING POSITION WHEN THE GATE VALVE IS OPEN AND THE BURNER IS TO BE OPERATED. A SEAL PROVIDED BY COOPERATING FLANGES ON THE FIXED AND MOVABLE SECTION PREVENTS LEAKAGE WHEN THE TERMINAL SECTION IS FULLY EXTENDED. THE FIXED INNER SECTION HAS AN OFFSET BOTTOM TO PROVIDE A DUST-COLLECTING SPACE.

Jan. 19, 1971v s. P. KINNEY ETAL 3,

BLAST FURNACE STOVE BURNER ASSEMBLY Filed May 28, 1969 I 3 Sheets-Sheet 1 INVENTOR.

Selwy nePKinneg. Hugh B. Carr. l m 4. W Lv Attorneys.

N o a c c I Q.

s. P. KINNEY E AL I 3,556,702

BLASI FURNACE STOVE BURNER ASSEMBLY Jan. 19, 1971 3 Sheets-Sheet 8 Filed May 28, 1969 Jan. 19, 1971 s. P. KINNEY ETAL 3,556,702

BLAST FURNACE STOVE BURNER ASSEMBLY Filed May 28, 1969 3 Sheets-Sheet 5 INVENTOR.

Huqfi 8. Curr. M, my 1 10, 4,

Attorneys.

Selwqne P. Kinney.

3,556,702 BLAST FURNACE STOVE BURNER ASSEMBLY Selwyne P. Kinney, Carnegie, and Hugh 13. Can, Mc-

Murray, Pa., assignors to S. P. Kinney Engineers, Inc., Carnegie, Pa., a corporation of Pennsylvania Filed May 28, 1969, Ser. No. 828,557

Int. Cl. F23c /06 US. Cl. 431-186 3 Claims ABSTRACT OF THE DISCLOSURE A gas burner for use on a blast furnace stove is disclosed wherein there are inner and outer concentric passages for the air and gas. There is a gate valve interposed between the end of the burner, and the inner passage is provided with a terminal section that telescopically engages a fixed inner duct section in such manner that it can be retracted when the gate valve is to be closed and extended to operating position when the gate valve is open and the burner is to be operated. A seal provided by cooperating flanges on the fixed and movable sections prevents leakage when the terminal section is fully extended. The fixed inner section has an offset bottom to provide a dust-collecting space.

BACKGROUND OF THE INVENTION This invention is for an improved gas burner especially designed for use on a blast furnace stove. It is of course well known that the usual furnace stove is a vertically elongated cylindrical structure with an internal combustion chamber extending up the inside wall and terminating below the top while the remainder of the interior is filled with checkerbrick through which the hot combustion gases flow downwardly to a flue outlet at the bottom. There is a burner port in the stove near the bottom of the combustion chamber and a flame is generated in the combustion chamber by a burner on the exterior of the stove with a discharge end entering the burner port. When the checkerbrick has been heated by burning gases from the combustion chamber, the stove is bottled up for later use, or immediately put on blast when air is blown upwardly through the checkerbrick and heated thereby, 'with the air passing out through a hot blast valve of the stove to the blast furnace. When the stove is on blast, or even when it is bottled up, the burner must be protected against the back flow of gases into the burner. The burner therefore includes a valve designed to prevent the back flow of gases through it when it is closed, but which is opened when the burner is operating.

The burner itself generally comprises an outer duct-like shell that extends into the burner port of the stove. Extending coaxially within the outer shell is a concentric inner duct. Provision is made for introducing combustible blast furnace gas into one duct and air into the other. Typically the inner duct is an air duct and the surrounding one is a gas duct, but they may be reversed. Valve arrangements for closing both duct or passages have commonly been quite complicated, or the burner had to be constructed so that premature mixing of the gas and air took place.

In Kinney Pat. 3,086,582 granted Apr. 23, 1963 and owned by our assignee, an improved arrangement is disclosed wherein the inner duct of the burner is formed of three sections in end-to-end relation, the front and rear ones being fixed while the intermediate one is movable axially, telescoping over the outermost one which is the one most remote from the burner port and abutting the inner one when the burner is operating. This enables a simple gate valve to be located in the outer duct, so that the gate could be closed when the intermediate inner duct section is retracted but which forms a continuous inner duct when the valve is opened. While this has been a subnited States Patent 0 m 3,556,702 Patented Jan. 19, 1971 stantial improvement, the fixed inner end or discharge section of the burner was exposed to the internal heat of the stove at all times when the burner was not firing, and even though a ceramic covering was applied over the inner section, it did not have the life expected of it.

BRIEF SUMMARY OF THE INVENTION This invention is for an improvement in the construction shown in Pat. 3,086,582 in which a simple gate valve is part of the burner but all parts of the burner are outside the burner port of the stove when the stove is on blast or is bottled-up. The burner comprises a gate valve body, adjacent a burner orifice in the blast furnace stove having a gate valve therein, an outer duct attached to the gate valve body and a concentric axially extending inner duct having a fixed section and a telescopic section. When in operation, the gate valve is opened and the telescopic inner section projects through the open valve into the burner port of the stove, with the inner duct directing air into the combustion chamber while the outer duct directs the gas into the combustion chamber. A seal is provided between the telescopic and relatively fixed sections of the inner duct and preferably the relatively fixed section is of semi-elliptical cross-section to provide a dust-collecting space and dust removal therefrom without damaging the telescoping section.

BRIEF DESCRIPTION OF THE DRAW'INGS FIG. 1 is a horizontal longitudinal section through the burner and a portion of the stove;

FIG. 2 is a fragmentary sectional view on a larger scale of the sealing means between the telescopic section and relatively fixed section of the inner duct;

FIG. 3 is a side elevational view of the burner of the present invention with the stove and gate valve body shown in vertical longitudinal section;

FIG. 4 is an end elevation of the outer end of the burner with the stove and gate valve body not shown; and

FIG. 5 is a transverse vertical sectional view in the plane of line VV of FIG. 3 with the telescopic section in retracted position.

DETAILED DESCRIPTION Referring to FIG. 1, there is illustrated in horizontal cross-section the burner of the present invention in position on a blast furnace stove, the stove having an outer shell 1, a refractory inner lining 3 and a burner opening or port 5. The port 5 is generally lined with a refractory sleeve 9 that projects beyond the stove and which is partially confined within a fixed ring 7 having a flange 11 at its outer end. Bolted by flange bolts, not shown, or otherwise attached to the flange 11 is a gate valve body 15. The gate valve body can be of conventional construction having ability to withstand the high temperature of the stove, such as those hot blast valves used in the dust leading from the stove to a blast furnace, and are well known. The valve body generally has a bonnet to receive the valve disc which is water-cooled, when the disc is raised out of the opening. There are water-cooled rings or seats around the interior of the valve body against which the disc seals when the valve is closed.

To the side of the valve body opposite flange 13 there is attached by means of flange 19 and flange bolts not shown, or otherwise, the burner having outer duct 17 for the passage therethrough of gas. Generally, the cross section of the duct 17 is the same as that of the disc in valve body 15 and the burner orifice 5, although some variance in the relative cross-section could be acceptable. Situate within duct 17 there is a concentric axially-extending inner duct comprising a relatively fixed section 21 and a telescopic section 23, the telescopic section 23 being movable in an axial direction. The relatively fixed section has an open end 22 terminating near but outwardly from the plane of the valve body and its opposite end is closed with plate 25. As shown in FIG. 1, the telescopic section 23 is movable axially so as to extend through the open gate valve 15 and into port 5 of the stove, with the outer end 24 of the telescopic section 23 projecting into the stove. In this position, air fed to the inner duct by the angularly extending air supply connection 29 will be directed through fixed section 21, telescopic section 23 and into the stove while gas, fed to outer duct 17 by vertical supply connection 31 is directed into the stove, the air and gas streams being kept separate until both streams enter the stove through port 5, preventing combustion of an air-gas mixture prior to injection into the stove.

A sealing means is provided between the telescopic section 23 and the fixed section 21, when the telescopic section is extended, so as to prevent combustion at the joint when the burner is in operation. An especially useful sealing means is shown in detail in FIG. 2, where the relatively fixed section 21 has an inwardly extending flange 63 around the periphery of the open end 22 and the telescopic section 23 has at the inner end 26 an outwardly extending flange 61, which contact each other when the section 23 is extended to its operating position. A sealing gasket 65 of silicone resin or other heat resistant material is carried in a groove in one of the confronting faces of these flanges, being here shown in the flange 61 of the movable section. Thus, when flange 63 is in contact with flange 61, the ring seals the joint and prevents combustion at this joint and any resulting deterioration therefrom.

To provide axial movement of the movable duct section 23 there is a spider 33 at the inner end of the section 23 to the center of which is attached an operating rod assembly 35 that extends rcarwardly through the closure plate 25 to an operating mechanism, designated generally as 36. As here shown, this rod assembly comprises an internally threaded sleeve 38 into which extends the threaded end of a rod 37. By rotating the rod 37 relative to sleeve 38, the movable inner duct section 23 may be moved in or out and firmly retained in its extended and retracted positions against accidental displacement. The threaded sleeve 38 is rigidly supported in a slide bearing 40 carried at the outer end of gusset plates 42 attached to the rear closure plate 25. There is a dust excluding tube or shield 44 extending from the bearing 40 to the plate 25 to protect the threaded connection between sleeve 38 and rod 37 from dust. The sleeve 38 is held from turning by a longitudinal key 38a engaged in a key slot not shown, in bearing 40, forming in effect a spline. Lubricant may be supplied to the bearing 40 through nipple 45 and tube 45a. A peep sight 43 is provided on closure plate 25 for observation of the interior of the burner.

The rod 37 may be rotated by a motor 41 or a hand wheel 39 which rotates the rod through a pinion (not shown) splined on the rod 37 in a known manner. The rod extends rearwardly of the drive 36 into a tube 46 where a nut with an indicator 45 is caused to travel on the threaded rear end of the rod simultaneously with and in the same direction along a slot in the tube 36 to show externally of the burner the exact position of the movable duct section 23. This operating means in which pressure is exerted and held through the screw connection assures that a good seal will be maintained between the confronting sealing flanges and the gasket when the movable terminal section of the inner duct is fully extended.

A closure ring 27 is provided, at the outer end of duct 17 which extends from the outer duct 17 to the fixed section 21 of the inner duct and closes that end of outer duct 17. There is also provided on outer duct 17 a suitable explosion door mechanism 49 to provide a pressure release should backfiring or other excess pressure conditions occur.

To provide for removal of dust which is carried into the burner with the gas and air, there are provided, as best seen in FIG. 3, a gas passage clean-out extension with a removable closure 57 on the outer duct 17 and an air passage clean-out extension 51 that projects from the fixed section 21 of the inner duct and extends through outer duct 17 It has a removable closure 53. To prevent buildup of dust in the fixed section 21 of the inner duct that could interfere with the movement of the telescopic section 23, it is advantageous to have the fixed section 21 of a semi-eliptical section, with the lower half curved on a longer radius than the upper half as shown in FIG. 5. This configuration provides an offset or space 28 below the bottom of the telescopic section 23 when that section is retracted into the fixed section 21 of the inner duct, wherein dust may collect without interfering with the axial movement of telescopic section 23.

In the foregoing description the inner duct has been referred to as an air duct and the outer duct as a gas duct, since this will more readily accommodate to the burner to the air and gas lines of most blast furnace stoves, but this may be reversed where the air and gas lines more readily accommodate such reversal. In either event, the air and gas is kept separate when the burner is operating until the gases are discharged into the combustion chamber of the stove. The individual gas and air valves customarily provided on the connections 29 and 31 according to standard practice are not shown.

There has been described a burner assembly for a blast furnace stove that is located entirely exterior of the stove and, instead of any parts thereof being subject to temperature variations generally between 700 F. and 2300 F. which causes severe deterioration of exposed parts, the gases will cool the burner when it is operating and when the gate valve is closed and the stove is on blast, any parts outwardly from the gate valve are protected from the high temperature in the stove and heat is dissipated both from the gate valve and the burner ducts to the ambient air. The maximum temperatures reached by the burner parts is therefore of the order of 350 F., and this makes possible the use of a sealing ring of silicone resin.

We claim:

1. For use with a blast furnace stove having a burner port, a burner assembly for supplying air and combustible gas in separate streams to the burner port comprising,

(a) a gate valve body with a reciprocable gate arranged to be attached to the burner and with a passage through the valve body that registers with with the burner port when the valve is so attached,

(b) a generally cylindrical outer duct attached at one end to the valve body through which one of said two gases is supplied through the valve to the burner port,

(c) a coaxially extending inner duct within the outer duct through which the other of said gases is supplied to the burner port, said inner duct comprising a fixed section in that end of the outer duct remote from the valve and a movable terminal section telescopically engaging the fixed section and movable from a retracted position where it is entirely witihn the outer section to an extended position where it projects beyond the valve confronting end of the outer duct a distance sufficient to pass through the passage in the valve body and extend into the burner port so that when the movable section is so extended the gases from the inner and outer ducts first mix in the port in an area spaced from the valve body, said fixed and movable sections of the inner duct having cooperating annular flanges thereon which are in confronting contact with each other when the movable section is fully extended, the flange on one section having a sealing gasket extending around the flange confronting face thereof, and

(d) means accessible at the exterior of the outer duct 6 for eifecting movement of the movable terminal secthrough the outer section with a removable closure at tion between the retracted and extended position. its outer end. 2. A burner assembly as defined in claim 1 in which References Cited the operating means for moving the movable section com- UNITED STATES PATENTS prises screw threaded rod assembly sections through which 5 pressure may be exerted to hold the confronting flanges 1,878,926 9/1932 Yirrow 43 1*186X in gas tight sealing engagement, 1086,58? 4/1963 Klnney 431187X 3. A burner assembly as defined in claim 1 in which the lower part of the fixed inner section is offset to pro- CARROLL DORITY Pnmary Exammer vide a dust collecting space below the path of movement of the movable inner section when it is retracted, 10

and there is a dust cleanout extension opening into said 431187; 239424 offset lower part of the fixed section and which passes 

